The invention relates to improvements in methods and apparatus for making rod-shaped articles of the tobacco processing industry. More particularly, the invention relates to improvements in methods and apparatus for making rod-shaped articles of the type wherein two or more rod-shaped components are joined end-to-end, for example, by uniting bands customarily used in filter tipping machines. Typical examples of rod-shaped articles which can be produced in accordance with the method and in the apparatus of the present invention are filter cigarettes, cigar, cigarillos, stogies and cheroots as well as composite filters and mouthpieces for tobacco smoke. The following description will deal primarily with the making of filter cigarettes; however, the same method and the same apparatus can be resorted to for the making of aforementioned composite rod-shaped articles other than filter cigarettes.
A modern filter tipping machine (e.g., the machine known as MAX 90 which is produced and distributed by the assignee of the present application) is designed to simultaneously produce a plurality of filter cigarettes of unit length. Reference may be had, for example to U.S. Pat. Nos. 4,823,932, 4,825,883 and 4,841,993 to Hinz et al. To this end, the machine is provided with devices which accumulate a series of rod-shaped articles (including pairs of plain cigarettes of unit length and a filter plug of double unit length between the plain cigarettes) into spaced-apart parallel groups each of which contains several coaxial rod-shaped articles. The groups are conveyed sidewise or sideways (namely at least substantially at right angles to their axes) and are connected to each other by uniting bands (e.g., each such group can constitute a filter cigarette of double unit length). Successive groups (wherein the components are connected to each other) are subdivided into pairs of discrete rod-shaped articles (such as pairs of filter cigarettes of unit length). The discrete articles of each pair are mirror images of each other and, therefore, the machine is provided with a turn-around device or inverting means serving to turn one discrete article of each pair end-for-end and to place the inverted article between a pair of non-inverted articles so that the inverted and non-inverted articles form a single stream which can be admitted into storage, into a packing machine or delivered to another station.
Simultaneous making of pairs of discrete rod-shaped articles (such as filter cigarettes of unit length) is desirable and advantageous because the output of the machine is doubled. The spacing of successive groups and successive discrete articles from each other (as measured at right angles to the axes of the groups and articles) is determined by the maximum spacing which is required in connection with a particular operation during assembly of the groups, during connection of components of successive groups to each other, during severing or subdivision of the groups into pairs or larger numbers of discrete articles or during treatment of discrete articles. Such spacing is maintained from the beginning to end, i.e., from the locus of assembly of groups of coaxial rod-shaped components to the locus where the finished products leave the machine.
Published German patent application No. 35 23 129 discloses a tipping machine with two mechanisms (called rolling units) which are used to connect successive groups of two or more coaxial rod-shaped articles to each other by means of adhesive-coated uniting bands. The speed of groups which are about to be provided with and surrounded by adhesive-coated uniting bands is reduced to approximately one-third of the initial speed, and successive decelerated groups are alternately delivered to the first and second rolling units to be thereupon reassembled into a single row of groups each having two or more interconnected components. The speed of the groups is increased back to the initial speed as soon as they are reassembled downstream of the two rolling units.
Commonly owned U.S. Pat. No. 4,827,947 to Hinz discloses a filter tipping machine wherein the mutual spacing of successive articles is reduced for the purpose of making air-admitting openings (perforations) in their tubular wrappers. However, and as can be seen in FIG. 2 of the patent, the initial spacing is restored as soon as the rod-shaped articles advance beyond the perforating station.